Overview of the 15-inch PowerBook G4

This chapter outlines the features of the 15-inch PowerBook G4, with emphasis on the changes from the previous model.

New Features

The features that have changed are listed here along with references to the sections that describe them. For a quick summary of the feature comparison of this model to the previous release model, see Table 1-1.

Table 1-1  Basic Feature comparison

Feature

Previous model

Current model

Processor

PowerPC G4

Enclosure

aluminum alloy

Processor clock speed

1.5 GHz or 1.67 GHz

1.67 GHz

Graphics IC

ATI Mobility Radeon 9700

System bus speed

167 MHz

Device ports

2 USB 2.0; 1 FireWire 400 ; 1 FireWire 800

Graphics memory

64 MB of DDR; BTO: 128 MB with dual link DVI

128 MB with dual link DVI

Hard disk drive

80 GB 5400 rpm. BTO: 100 GB 5400 rpm

80 GB 5400 rpm. BTO: 100 GB or 120 GB 5400 rpm; 100 GB 7200 rpm

Optical drive

Combo drive or 8x SuperDrive

double-layer burning 8x SuperDrive. BTO: Combo drive

Audio

audio line in, headphone out, microphone, and stereo speakers

combined audio line-in and optical digital audio input port, combined headphone output and optical digital audio output port, microphone, and stereo speakers

Keyboard

backlit keyboard and ambient light sensors

RAM

512 MB PC2700 DDR SDRAM SO-DIMMs running at 333 MHz with 2 GB expansion capacity

512 MB PC2-4200 DDR2 SDRAM SO-DIMMs running at 333 MHz with 2 GB expansion capacity

Wireless

AirPort Extreme and fully-integrated Bluetooth 2.0 +EDR

AirPort Extreme and Bluetooth 2.0 +EDR combined into a single module

Battery

50 watt-hours battery with up to 4.5 hours operation

50 watt-hours battery with up to 5.5 hours operation

Power adapter

65 W power adapter

note: BTO — build to order

All Features

Here is a list of the features of the 15-inch PowerBook G4 computer. Each feature is described in a later chapter, as indicated in the list.

Appearance

Figure 1-1 is a front view of the 15-inch PowerBook G4 computer. Figure 1-2 provides side views that show the I/O ports.

Figure 1-1  Front view of the computer
Front view of the computer
Figure 1-2  Side views showing I/O ports
Side views showing I/O ports

Peripheral Devices

In addition to the devices that are included with the computer, several peripheral devices are available separately:

System Software

The 15-inch PowerBook G4 comes with Mac OS X version 10.4.2 installed and runs Mac OS 9 applications in Classic mode. For the latest information, see the references listed in Mac OS X.

Here are a few items of interest about the system software on the 15-inch PowerBook G4.

Open Firmware

System software on all current Macintosh models uses a design based on Open Firmware. With this approach, the ROM on the main logic board contains only the Open Firmware code needed to initialize the hardware and load an operating system. The rest of the system code is loaded into RAM from disk or from the network. For more information, see the references listed in Open Firmware.

Computer Identification

Rather than reading the box flag or the model string and then making assumptions about the computer’s features, applications that need to find out the features of the computer should use IORegistry calls to test for the features they require. IORegistry calls are part of the IOKit API. For more information, see the references listed at IOKit.

Asset management software that reports the kind of computer it is running on can obtain the value of the model property from the IOService plane of the IORegistry. For the 15-inch PowerBook G4, the value of the model property is PowerBook5,8.

Power Management

Apple’s power management techniques for the 15-inch PowerBook G4 are described in the following paragraphs.

Power Saving States

The power management protocols on the 15-inch PowerBook G4 support two power-saving states: idle and sleep.

  • Idle: The system is idling with the main processor in a low-power state. All clocks are running; the system can return to running code within a few nanoseconds. Cache coherency is maintained in this state. The CPU automatically transitions between run and idle, independent of the operating frequency. The operating frequency is based on the processor power management setting. For additional information, see Processor Power Management.

  • Sleep: Most internal components are powered off and the state is saved; the DRAM state is preserved for quick recovery. All processors are powered off with their state preserved in DRAM. All clocks in the system are suspended except for the 32.768 kHz timebase crystal on the PMU05 IC.

The computer automatically enters idle state after a few hundred miliseconds of inactivity. If the computer is attached to a network, it is able to respond to service requests and other events directed to the computer while it is in idle state.

While it is connected to an AC power supply, the computer can also respond to network activity when it is in sleep state. The user can enable this feature by selecting Wake-on-LAN in the Energy Saver preference pane.

When operating on the battery in sleep state, the computer consumes less than 1 watt of power, meeting the Energy Star power-saving standard. When operating on the power adapter in sleep state, the combined computer and adapter consume up to 3 to 4 watts of power.

Processor Power Management

To lower power consumption and heat generation, the 15-inch PowerBook G4 incorporates an automatic power management stepping technique. Stepping is designed to run at full, half, or quarter processor speed and voltage to meet the demands on the processor. The processor speed will switch between 1670 MHz and 833 MHz at 1.28 V for divide by 2 and between 1670 MHz and 417 MHz at .93 V for divide by 4. The memory bus speed is not shifted.

If the 15-inch PowerBook G4 detects a system temperature that is high, due to high ambient temperatures or other factors, it will immediately force the system to quarter speed mode.

The 15-inch PowerBook G4 meets all applicable safety standards, including UL 60950 and IEC 60950.

Graphics Power Management

For additional power savings and reduced heat generation, the 15-inch PowerBook G4 incorporates a dynamic graphics power management technique. When required, the graphics processor runs at a reduced voltage and slower clock rate, similar to stepping on the central processor.



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